Journal of South American Earth Sciences 68 (2016) 4e21

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Journal of South American Earth Sciences

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The ArcheanePaleoproterozoic evolution of the Quadrilatero Ferrífero (Brasil): Current models and open questions

* F. Farina , C. Albert, C. Martínez Dopico, C. Aguilar Gil, H. Moreira, J.P. Hippertt, K. Cutts, F.F. Alkmim, C. Lana

Departamento de Geologia, Universidade Federal de Ouro Preto, Morro do Cruzeiro, 35400-000 Ouro Preto, MG, Brazil article info abstract

Article history: The Quadrilatero Ferrífero is a metallogenic district (Au, Fe, Mn) located at the southernmost end of the Received 29 June 2015 Sao~ Francisco craton in eastern Brazil. In this region, a supracrustal assemblage composed of Archean Received in revised form greenstone and overlying NeoarcheanePaleoproterozoic sedimentary rocks occur in elongated keels 30 September 2015 bordering domal bodies of Archean gneisses and granites. The tectonomagmatic evolution of the Accepted 27 October 2015 Quadrilatero Ferrífero began in the Paleoarchean with the formation of continental crust between 3500 Available online 3 November 2015 and 3200 Ma. Although this crust is today poorly preserved, its existence is attested to by the occurrence of detrital zircon crystals with Paleoarchean age in the supracrustal rocks. Most of the crystalline Keywords: Quadrilatero Ferrífero basement, which is composed of banded gneisses intruded by leucogranitic dikes and weakly foliated e Archean granites, formed during three major magmatic events: Rio das Velhas I (2920 2850 Ma), Rio das Velhas Paleoproterozoic II (2800e2760 Ma) and Mamona (2760e2680 Ma). The Rio das Velhas II and Mamona events represent a Tectonomagmatic evolution subduction-collision cycle, probably marking the appearance of a modern-style plate tectonic regime in Sao~ Francisco craton the Quadrilatero Ferrífero. Granitic rocks emplaced during the Rio das Velhas I and II events formed by mixing between a magma generated by partial melting of metamafic rocks with an end member derived by recycling gneissic rocks of older continental crust. After deformation and regional metamorphism at ca. 2770 Ma, a change in the composition of the granitic magmas occurred and large volumes of high-K granitoids were generated. The ca. 6000 m-thick Minas Supergroup tracks the opening and closure of a basin during the Neo- archeanePaleoproterozoic, between 2600 and 2000 Ma. The basal sequence involves continental to marine sediments deposited in a passive margin basin and contain as a marker bed the Lake Superior- type Caue^ Banded Iron Formation. The overlying sediments of the Sabara Group mark the inversion of the basin during the Rhyacian Minas accretionary orogeny. This orogeny results from the collision be- tween the nuclei of the present-day Sao~ Francisco and Congo cratons, generated the fold-and thrust belt structure of the Quadrilatero Ferrífero. Afterwards, the post- orogenic collapse resulted in the deposition of the Itacolomi Group and in the genesis of the dome-and-keel structure. In this paper, we review current knowledge about the 1500 Ma long-lasting tectonomagmatic and structural evolution of the Quadrilatero Ferrífero identifying the most compelling open questions and future challenges. © 2015 Elsevier Ltd. All rights reserved.

1. Introduction (“Iron Quadrangle”). This region, which has been an important mining site since the XVII century, represents the most intensively In the mid-twentieth century, the ca. 7000 km2 portion of the studied region of Brazil. Its valuable iron deposits together with its Brazilian highlands south of the city of Belo Horizonte (Fig. 1) puzzling geological complexity have attracted the attention of became well-known under the name of Quadrilatero Ferrífero many scientists over the last century. The goal of the present paper is to provide an up-to-date state of the art about the geology of the Archean crystalline basement and ArcheanePaleoproterozoic metasedimentary sequences forming the Quadrilatero Ferrífero. * Corresponding author. This review, focussed on the Archean and Paleoproterozoic E-mail address: [email protected] (F. Farina). http://dx.doi.org/10.1016/j.jsames.2015.10.015 0895-9811/© 2015 Elsevier Ltd. All rights reserved. F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 5

Fig. 1. Geological map of the Quadrilatero Ferrífero modified after Alkmim and Marshak (1998). Batholith and pluton abbreviations: C- Caete dome, F- Florestal, M- Mamona, P- Pequi, Sa- Samambaia; SN- Souza-Noschese. Inset: tectonic sketch of the Sao~ Francisco craton showing the location of the bordering Brasiliano orogenic belts as well as of the Paleoproterozoic Mineiro Belt. Abbreviations: G, J, IS and S are the Gaviao,~ Jequie, Itabuna-Salvador-Curaça and Serrinha blocks, respectively. evolution of this portion of the southern Sao~ Francisco craton, is not panning and sluicing in shallow water stream) slowly declined aiming to be exhaustive. Some important topics will not be (Costa et al., 2003). addressed (e.g. the origin of ore deposits) while others will be only In 1810, the mineralogist and geologist Baron Wilhelm Ludwig briefly presented (e.g. the structural evolution). The goal of this von Eschwege arrived to Brazil entrusted by the king Dom Joao~ VI to contribution is to discuss the present-day petrologic and geo- study the ores and the mining activity with the goal of imple- dynamic models proposed for the Quadrilatero, drawing attention menting new mining techniques to increase gold production. The to the main open problems and limitations in an attempt to high- baron made a significant step forward in the description and un- light future challenges and favourable research directions. derstanding of the geology of the Quadrilatero Ferrífero. Eschwege published various books (e.g. Pluto brasiliensis (1833)) in which he outlined the main geological features of the Precambrian terranes 2. Historical background and geographic boundaries of central Brazil proposing a stratigraphic subdivision according to Werner's Neptunism theory. In the sixteenth century, the discovery of large gold and silver In the early nineteenth century, the gold-rich region around deposits in the Spanish colonial possessions in South America Ouro Preto returned to the spotlight because of its iron and man- triggered the Portuguese empire to embark in the exploration of ganese deposits. One century after Eschwege arrived in Brazil, the inland Brazil seeking precious metals. For ca. 100 years the hunt for American geologist Derby published a work titled “The iron ores of payable precious metals proved futile and only in 1646 the first Brazil” that attracted the interest of the mining community to the discovery of small alluvial gold deposit in Brazil was made in the iron and manganese deposits of Minas Gerais. In the mid-twentieth southern state of Parana( Figueiredo, 2011). In 1693, the first gold century, an agreement was set between the Brazilian National placer deposit was found in southeastern Brazil (state of Minas Department of Mineral Production (DNPM) and the U.S. Geological Gerais), close to the city of Ouro Preto (“black gold” in Portuguese). Survey to undergo the first detailed geological study of the region The discovery of many rich gold deposits in the region that is today where the main iron and manganese deposits were located known as the Quadrilatero Ferrífero, revitalized Brazil's economy (Machado, 2009). This agreement and the two decades of work that causing such a stir that, by the end of the century a considerable followed marked the most important step forward in the under- proportion of Brazil population had rushed to the site of the dis- standing of the geology of the Quadrilatero Ferrífero. The outcome covery (Costa et al., 2003). More significantly, as news of the dis- of this joint project was a set of geological maps in the 1:25.000 covery spread to the mother country, thousands of Portuguese scale followed by a stratigraphic column and a report written by the adventurers moved to Brazil at the turn of the eighteenth century: head of the team, John Van N. Dorr II, in which the main geological the first great gold rush had begun. Between 1693 and 1720, the features of the studied region were defined. Dorr and collaborators population of the gold-rich province grew exponentially. Such was coined the term Quadrilatero Ferrífero in 1952 (Machado, 2009)to the growth that half Brazil's entire population was residing in give credit to the abundance of high-grade iron ore deposits in the Minas Gerais in 1725. Gold production increased as the eighteenth region. These authors defined the geographic boundaries of the century advanced, peaking around mid-century and then, due to Quadrilatero producing a detailed 1:150.000 geological map. Oddly, the rudimental mining technique implemented (e.g. mostly 6 F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 as shown in Fig. 1, the “iron quadrangle” of Dorr and collaborators is three main groups: not a quadrangle but rather a complex polygon, including the Ita- bira mining district. The reason for the use of the term Quadrilatero i) fine-grained banded orthogneisses intruded by (ii) and (iii); proposed by Dorr is historical. In fact, the term was introduced in ii) leucogranites and aplitic/pegmatitic veins and dikes; 1923 by the Brazilian geologist Flores de Moraes Rego to define the iii) medium-to coarse-grained, mostly weakly foliated granites four-sided area comprised between the cities of Belo Horizonte, (sensu lato). Santa Barbara, Congonhas and Mariana (Machado, 2009). Clear geographic features do not delimit the Quadrilatero Ferrífero as The gneisses are characterised by the alternation between leu- defined and mapped by Dorr and collaborators and thus, the term cocratic and mesocratic, or more rarely, melanocratic bands, vary- has been used loosely to describe the geology of areas that are not ing in width from 2 mm to up to 10 cm and defining a penetrative part of the original map of the Quadrilatero. As shown in Fig. 1,we amphibolite-facies foliation (Fig. 3a and b). The mesocratic bands will also extend the limits of the Quadrilatero Ferrífero to include are rich in plagioclase and biotite and display lepidoblastic textures, the Bonfim and the Belo Horizonte domes in their entirety. whereas the leucocratic ones, containing predominantly plagio- clase, quartz and minor microcline, show granoblastic textures 3. Main geological features (Lana et al., 2013). Alkali-feldspars are generally interstitial, but they occasionally form cm-scale phenocrysts. A subset of gneiss The Sao~ Francisco Craton in eastern Brazil is one of the major samples show complex polydeformed structural patterns exhibit- and probably the best-exposed shield area forming the South ing disharmonic folding of the banding associated to high volumes American platform. The craton is subdivided into several Archaean (up to 20 vol.%) of non-foliated leucogranitic material forming to Paleoproterozoic blocks bounded by major ca. 2100 Ma old su- folded sheets as well as decimetric pods. Locally, some outcrops tures zones (Teixeira and Figuereido, 1991; Barbosa and Sabate, display an even more chaotic aspect with boudinaged and 2004) and surrounded by Neoproterozic fold-belts (e.g. the Ara- dismembered gneiss fragments isolated in a granitic matrix. Farina çuaí belt; Pedrosa-Soares et al., 2001). Four crustal segments form et al. (2015a) interpret these rocks as migmatites. the northern part of the craton (Barbosa and Sabate, 2004): the The gneisses are typically intruded by multiple, meter-to cm- Gaviao,~ Jequie, Serrinha and Itabuna-Salvador-Curaça blocks scale leucogranitic sheets sub-parallel to the gneissosity as well as (Fig. 1). To the south, the Sao~ Francisco Craton comprises various by crosscutting younger felsic and/or pegmatitic dikes (Lana et al., granitoid-gneiss complexes (i.e. Campo Belo, Passa Tempo, Bonfim, 2013). Foliated or massive leucogranitic sheets are oriented sub- Belo Horizonte, Baçao,~ Caete) and ArcheanePaleoproterozoic parallel to the banding and have thickness of up to 60 cm (Fig. 3c supracrustal sequences and hosts the Quadrilatero Ferrífero mining and d). A younger generation of leucogranitic, pegmatitic and district. The Quadrilatero Ferrífero occupies the eastern part of the aplitic dikes that crosscut both the gneissic banding and the leu- Southern Sao~ Francisco Craton and is fringed by the Late Neo- cogranitic sheets have widths reaching a maximum of about 2 m proterozoiceCambrian Araçuaí belt to the east and by the Paleo- (Fig. 3c). These dikes are only occasionally slightly folded or bou- proterozoic Mineiro Belt to the south (Fig. 1). This district exhibits dinaged, but in general appear little stretched, nor shortened. NNW-verging folds and thrusts and has a metamorphic overprint at Granitic rocks form texturally and compositionally composite about 2100e2000 Ma, which was originally known as the “Minas large batholiths (e.g. the Mamona batholith, Fig. 1) as well as diastrophism” (e.g., Cordani et al., 1980). The distinctive structural decimeter-to meter-scale domains and stocks intruded in or closely architecture of the Quadrilatero is its dome-and keel geometry, in associated with the banded gneisses (Farina et al., 2015a). Although which belts of low-grade Paleoproterozoic supracrustal rocks sur- typically weakly foliated, granitoids may also locally develop pro- round medium to high-grade granitoid-gneiss Archean complexes late L > S fabric. The granitic rocks are medium-to coarse-grained (Marshak et al., 1997). The Quadrilatero Ferrífero can be subdivided and exhibit either equigranular or porphyritic textures ranging in into four ArcheanePaleoproterozoic lithostratigraphic units composition from tonalite to syenogranite. Based on their ferro- (Fig. 2): magnesian minerals, three rock types are recognised: biotite- bearing granodiorites and granites (Fig. 3e), two-mica granites (i) Archean metamorphic complexes composed of gneisses, and biotite- and amphibole-bearing tonalites and granodiorites. migmatites, and granitoids; The first group represents the most abundant granite-type while (ii) the Archean Rio das Velhas Supergroup, formed by low-to muscovite- and amphibole-bearing granitoids are rare, mostly medium-grade metavolcanic and metasedimentary rocks; cropping out in the Bonfim complex. The relationship between (iii) the NeoarcheanePaleoproterozoic Minas Supergroup, con- banded gneisses and granitoids is observable in some key outcrops sisting of low-to medium-grade metasedimentary rocks; in the Baçao~ and Bonfim complexes. The intrusion of granites into (iv) the Paleoproterozoic Itacolomi Group composed of meta- banded gneisses produces different features. From gneiss-to sandstones and conglomerates. granite-dominated outcrops, we observe: i) dikes of medium- grained granites cutting both the gneissic banding and the leu- In addition, the Quadrilatero Ferrífero includes small granite cogranite sheets; ii) complex intermingled gneiss-granite struc- bodies and pegmatite veins locally cutting the youngest strata of tures (Fig. 3f); iii) meter-to decametre-scale domains of granites the Minas Supergroup as well as different generations of mafic intruding the banded gneisses; iv) xenoliths of banded gneisses dikes showing contrasting metamorphic grade, composition and hosted within granites. trending direction. A stratigraphic section of the Quadrilatero Fer- rífero is presented in Fig. 2 and the different lithostratigraphic units 4.2. Geochemistry: medium- and high-K granitoids are described in the following paragraphs. Whole rock major and trace element data for granites and 4. The Archean metamorphic complexes gneisses in the Quadrilatero Ferrífero is scarce, with different contributions generally investigating the compositional variability 4.1. Field relationships and petrography of individual complexes without attempting any regional-scale correlation (Carneiro and Teixeira, 1992; Noce et al., 1997). An In the field, the rocks of the basement can be subdivided into exception to this approach is represented by the work of Farina F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 7

Fig. 2. Stratigraphic column of the supracrustal sequences in Quadrilatero Ferrífero. Abbreviations: RVI and RVII are Rio das Velhas I and II events, SB is the Santa Barbara magmatic event. Modified after Dorr (1969) and Alkmim and Marshak (1998). et al. (2015a,b) in which a large database of chemical compositions and Rb than high-K rocks (Fig. 5). In addition, medium-K granitoids for the granites and gneisses of the Baçao,~ Bonfim and Belo Hori- have relatively high contents in light Rare Earth Element (LREE; i.e. zonte complexes was produced. In Figs. 4e6, we plotted the major average LaeSm ¼ 120 ppm) and low heavy Rare Earth Element and trace element composition of gneisses and granitoids from the contents (HREE, i.e. average GdeLu ¼ 8.2 ppm), resulting in steep Baçao,~ Bonfim, Belo Horizonte and Caete complexes as well as the REE patterns (La/Yb up to 70) while high-K rocks exhibit less composition of dacites from the Rio das Velhas greenstone belt. A fractionated REE patterns with HREE contents that are significantly complete dataset of whole rock compositions is presented in the higher (average GdeLu ¼ 38 ppm) than those of medium-K rocks Electronic supplement (Table A). (Fig. 6). The two rock types display different Eu anomalies with no Gneisses, granitoids and leucogranites of the Quadrilatero Fer- Eu anomaly or slightly negative in the medium-K rocks and a well rífero are silica-rich (i.e. ca. 70% of samples have silica content pronounced Eu anomaly for high-K granitoids and gneisses. Over- higher than 72 wt.%) and all oxides are broadly negatively corre- all, medium-K2O rocks share similar chemical features with rocks of lated with SiO2 (Fig. 5a and b), except K2O that displays positive the Archean tonalite-trondhjemite-granodiorite (TTG) series while correlation. high-K granitoids are similar to high-silica I-type granites. The In the normative feldspar classification diagram for granitoids latter plot consistently in the field of biotite- and two-mica granites (AneAbeOr, O'Connor, 1965), most of the gneisses and granites plot recently defined by Laurent et al. (2014) for late-Archean granites either in the trondhjemite or in the granite fields (Fig. 4), with only (Farina et al., 2015a). the biotite- and hornblende-bearing Samambaia pluton described Finally, leucogranitic sheets and dikes, representing ca. 10% of by Carneiro (1992) plotting in the tonalite field. The two groups can the bulk crystalline basement exposed in the Quadrilatero Ferrífero, be distinguished in the K2O vs. SiO2 diagram where most of the display characteristic low to very low MgO þ Fe2O3tot contents trondhjemites of Fig. 4 plot in the medium-K field defined by Gill (0.2e1.1 wt.%) and scattered major element composition with K2O (1981) while granitic rocks plot in the high-K field (Fig. 5b). The ranging from 3.8 to 8.9 wt.% and silica between 71 and 76 wt.% occurrence of medium- and high-K gneisses and granitic rocks in (Fig. 6). In the SiO2 vs. Al2O3 diagram, they generate a quasi-linear the basement of the Quadrilatero Ferrífero is evident once the K2O/ negative trend and for equivalent silica contents they are slightly Na2O of the rocks is plotted in a frequency histogram (Fig. 5c): the enriched in Al2O3 and depleted in MgO and Fe2O3tot than both distribution is bimodal showing well-defined peaks at 0.4e0.6 and granites and gneisses (Fig. 5). The leucogranitic rocks exhibit Eu 1.2e1.6 K2O/Na2O. Systematic compositional differences exist be- anomalies varying from slightly negative to strongly positive (Eu/ tween medium- and high-K rocks. Medium-K gneisses and gran- Eu* ¼ 0.9e2.8), low REE contents and flat REE patterns resulting in itoids have higher Al2O3,Na2O, CaO and Sr as well as lower silica low La/Yb ratios (Fig. 6). 8 F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21

Fig. 3. Field photographs of the basement. (a) Banded gneiss, Baçao~ Complex. (b) Banded gneiss hosting cm-scale leucogranitic sheets following the gneissosity, Baçao~ Complex. (c) Leucogranitic sheets in a gneiss crosscut by a late fine-grained leucocratic dike. (d) Leucogranitic dike parallel to foliation in the banded gneiss, Baçao~ Complex. (e) Medium-grained granodiorite containing cm-sized K-feldspar and rare mafic enclaves, Mamona batholith, Bonfim Complex. (f) Domains of medium-to coarse-grained granitoid intruding banded gneisses, Bonfim Complex. Hammer for scale is 30 cm long in a, b, c, f and 35 in d. The coin in d is 2 cm in diameter.

Fig. 4. Normative An-Ab-Or triangle (O'Connor, 1965) showing the composition of gneisses, granites and leucogranites as well as the composition of Rio das Velhas dacites. The field for Archean TTGs is from Moyen and Martin (2012). Data are from Gomes (1985), Carneiro et al. (1992), Noce et al. (1997), Da Silva et al. (2000) and Farina et al. (2015a). F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 9

Fig. 6. Average chondrite-normalized REE patterns for high-K granites and medium-K gneisses and granitoids. The trace element pattern for high-K granites is obtained averaging the composition of eleven samples, patterns for medium-K gneisses and granitoids are from fifteen and sixteen samples, respectively. Data are from Farina et al. (2015a). The TTG field is based on the low-to high-pressure TTGs after Moyen (2011). Normalization values are from McDonough and Sun (1995).

of the Quadrilatero Ferrífero, spanning from 3220 to 2680 Ma. The first magmatic pulse, poorly preserved in the north-south elon- gated Santa Barbara complex (Fig. 1), ranges from 3220 to 3200 Ma, with these rocks representing the only Paleoarchean crust dated in the Quadrilatero Ferrífero so far. Most of the gneisses in the Quadrilatero Ferrífero formed during the following periods of magma production, the Rio das Velhas I and II events (Lana et al., 2013). The Rio das Velhas I period, which was originally supposed to have ages spanning between 2930 and 2900 Ma, has been recently expanded down to 2850 Ma by Farina et al. (2015a). Similarly, new geochronological data, of Farina et al. (2015a) rede- fine the time of the Rio das Velhas II period between 2800 and 2760 Ma. It is worth noting that two weakly deformed plutons intruded the orthogneisses during the Rio das Velhas II event at about 2770 Ma (i.e. the Caete and Samambaia plutons, Machado et al., 1992). The age of these granites suggest that the last regional metamorphic event in the Quadrilatero Ferrífero occurred in the early Neoarchean, during the Rio das Velhas II event. The occurrence of this metamorphic event is supported by the obser- vation that many magmatic zircon grains from the banded gneisses of the Rio das Velhas I period are overgrown by metamorphic rims yielding Rio das Velhas II ages (Lana et al., 2013). Just after the regional metamorphic event, the Quadrilatero Ferrífero underwent a new period of widespread magmatism between 2750 and 2680 Ma (Romano et al., 2013) that has been named by Farina et al. (2015a): the Mamona event. During this event, slightly-to non- foliated rocks were emplaced as large batholiths and small leu- Fig. 5. Harker diagrams for the igneous rocks of the Quadrilatero Ferrífero: (a) SiO2 vs. Al2O3, (b) SiO2 vs. K2O. Grey dots are TTGs from Moyen (2011). In (c), histogram cogranitic veins and dikes into the pre-existing deformed crust. showing the frequency of K2O/Na2O values exhibited by the rocks of the Quadrilatero Finally, a volumetrically minor event of granite production ac- Ferrífero. The bin width used is 0.2. The height of the bars represents the number of counting for less than 1% of the continental crust in the Quad- samples with the corresponding K2O/Na2O value. rilatero occurred at ca. 2612 Ma (Romano et al., 2013). Two leucogranitic-pegmatitic dikes analysed by Machado et al. ~ 4.3. Geochronology (1992) in the southern part of the Baçao complex gave Paleo- proterozoic UePb monazite ages (i.e. 2130 and 2122 Ma, Table E e A review of published UePb ages from the basement of the Data Repository). These ages match with U Pb data obtained Quadrilatero Ferrífero (Fig. 7 and Table B in the Data Repository) from metamorphic titanites from amphibolitic dikes (ca. 2050 Ma) ~ fi allowed for the identification of four main magmatic events (Farina and gneisses in the Baçao, Bon m and Belo Horizonte complexes et al., 2015a,b; Lana et al., 2013; Romano et al., 2013). These periods (Machado et al., 1992; Noce et al., 1998; Aguilar et al., 2015)aswell ~ of magmatic activity, described as the Santa Barbara (SB), Rio das as with the crystallization age of the Alto Maranhao suite (Noce ~ Velhas I (RVI), Rio das Velhas II (RVII) and Mamona, embody a et al., 1998; Seixas et al., 2013). The Alto Maranhao tonalitic- significant part of the protracted tectonomagmatic Archean history dioritic batholith, located on the southern edge of the 10 F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21

Fig. 7. Timeline showing 207Pb/206Pb zircon ages for intrusive and volcanic rocks of the Quadrilatero Ferrífero. Circles, squares, diamonds and triangles indicate the Baçao,~ Bonfim, Belo Horizonte and Santa Barbara complexes, respectively. White and dark grey symbols are for high and medium-K rocks, respectively. In black, mafic and intermediate dikes and metamorphic zircon ages. The vertical light grey fields indicate the different magmatic events: SB- Santa Barbara RdV I- Rio das Velhas I; RdV II- Rio das Velhas II; Mam- Mamona. Data are from Romano et al. (2013); Lana et al. (2013); Machado and Carneiro (1992); Machado et al. (1992); Noce et al. (1998); Noce et al. (1997); Chemale et al. (1993); Noce et al. (2005).

Quadrilatero Ferrífero, is part of the Mineiro Belt, formed during the turbiditic graywakes form the overlying lithofacies (lithofacies iv Rhyacian orogenesis of the South American platform (Seixas et al., and v). It is worth noting that the minor dacitic lava flows have a 2013). TTG signature, exhibiting high Na2O and Al2O3 contents (Fig. 5) and strongly fractionated Rare Earth Element patterns that are consis- tent with partial melting of garnet amphibolite sources (Da Silva 5. The Rio das Velhas Supergroup et al., 2000). Finally, the lithofacies at the top of the sequence (i.e. lithofacies vi) is formed by sandstones with herringbone cross- 5.1. Stratigraphy bedding, ripple marks and large-scale cross-bedding. This lith- ofacies is restricted to a small area northwest of the Baçao~ Complex The metavolcanic and metasedimentary rocks of the Rio das and was probably deposited in shallow marine environment. Velhas Supergroup form a typical Archean greenstone belt Overlying the Nova Lima Group, the Maquine Group represents sequence characterized by the association between mafic and ul- a 2000 m thick clastic association comprising conglomerates and tramafic rocks (komatiiteebasalt, Fig. 8a and b), evolved volcanic sandstones (Fig. 8c) that was described by Dorr (1969) as a flysch to (dacites) and volcaniclastic rocks and immature clastic sediments molasse-type sequence, consisting of a coarsening upward suc- (Dorr, 1969). These rocks are metamorphosed at greenschist to cession of sandstones getting more quartz rich and conglomeratic lower amphibolite-facies conditions and are commonly affected by toward the top. The Maquine Group was divided into two forma- hydrothermal alteration (Ladeira et al., 1983; Zucchetti et al., 2000). tions: the basal Palmital (O'Rourke, 1957) and the upper Casa Forte Many different stratigraphic subdivision were proposed for the Rio (Gair, 1962). The Palmital Formation was deposited in a marine das Velhas Supergroup (Baltazar and Zucchetti, 2007 and refer- environment as proximal turbidites while the Casa Forte Formation ences therein). A first level of classification was introduced by Dorr is interpreted as a non-marine alluvial fan e braided river deposit. (1969), which subdivided the greenstone belt into the Nova Lima The contact between the Nova Lima Group and the overlying and Maquine groups, the former occurring at the base of the sandstones and conglomerates of the Maquine Group is either sequence and hosting the major gold deposits of the Quadrilatero gradational or locally unconformable and marked by fault zones Ferrífero (Fig. 2). Recently, Baltazar and Zucchetti (2007), following (Dorr, 1969). The lack of a clear discordance between the Palmital the approach of Eriksson et al. (1994) subdivided the Nova Lima Formation and the top of the Nova Lima Group as well as the ma- Group into six sedimentary lithofacies associations forming four rine environment of deposition for the Palmital Formation led sedimentary cycles. From bottom to top these are: (i) mafic- Baltazar and Zucchetti (2007) to associate this formation to the ultramafic volcanic; (ii) volcano-chemical-sedimentary; (iii) coastal association defined in the Nova Lima Group. clastic-chemical-sedimentary, (iv) volcaniclastic; (v) re- sedimented and (vi) coastal. The basal lithofacies of the Nova Lima Group is made of mafic and ultramafic lavas intercalated with 5.2. Geochronology minor intrusions of gabbro, anorthosite and peridotite as well as with banded iron formation, ferruginous cherts, chemical carbo- UePb ages of detrital zircons from the Rio das Velhas greenstone naceous sediments and rare felsic volcaniclastic rocks. The ultra- belt were determined by Machado et al. (1992, 1996), Noce et al. mafic lavas are massive and pillowed komatiites characterized by (2005) and Hartmann et al. (2006) using different analytical tech- spinifex textures (Schorscher, 1978; Sichel, 1983), with layers of niques such as SHRIMP, LA-ICP-MS and ID-TIMS (Table C in the Data cumulus olivine/intercumulus orthopyroxene and a level of lahar- Repository). Eight of the nine samples analysed are greywackes type breccia (Baltazar and Zucchetti, 2007). This event of mafic from the Nova Lima group while only five zircon grains were ana- volcanism and carbonate precipitation was followed by submarine lysed for one sample collected by Machado et al. (1996) from the deposition of pelites, graywackes and quartzites with intercalated Maquine Group. Three volcaniclastic graywackes in the Nova Lima rocks of banded iron formation, quartzedolomites, quartz- Group gave maximum deposition ages of 2792 ± 11, 2773 ± 7 and eankerites (hosting the world-class Morro Velho gold deposit; 2751 ± 9 Ma, indicating ca. 40 Ma of felsic volcanism in the Lobato et al., 2001), conglomerates and carbonaceous phyllites (i.e. Quadrilatero Ferrífero (Machado et al., 1992, 1996; Noce et al., lithofacies ii and iii). Volcaniclastic and resedimented volcaniclastic 2005). The occurrence of a Neoarchean felsic volcanic event is rocks as well as minor lava flows of dacitic composition and supported by a zircon 207Pb/206Pb crystallization age of 2772 ± 6Ma F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 11

Fig. 8. Field photographs of the supracrustal rocks. (a) Komatiite showing spinifex structure, basal portion of the Nova Lima Group; (b) metabasalt with deformed pillow structure, basal portion of the Nova Lima Group; (c) polymictic conglomerate of the Maquine group containing stretched clasts; (d) Caue^ Itabirite showing the typical intercalation of hematite and quartz rich bands; (e) conglomerate of the Sabara Group containing clasts of quartzite, gneisses, granites and banded iron formation embedded in a chlorite-rich matrix; (f) Quartz metasandstone of the Itacolomi Group showing crossbedding. Crossbedding sets are marked by concentration of heavy minerals, especially iron oxides. The pens in b, c, d and e are 14 cm long. determined by Machado et al. (1992) for a dacitic flow intercalated stand out: within the sequence of mafic-to ultramafic volcanic rocks in the greenstone belt. Detrital zircons from two sandstones from the top The main magmatic event preserved in the metasedimentary of the Nova Lima Group dated by SHRIMP by Hartmann et al. (2006) rock record is the 2800e2760 Ma Rio Das Velhas II event; gave a maximum depositional age of 2749 ± 7 Ma. The second highest frequency peak is at ca. 2860 Ma matching UePb age data from detrital zircon grains in the Nova Lima the youngest limit of the Rio Das Velhas I event Group are plotted in the frequency diagram of Fig. 9. In this dia- (2920e2860 Ma); gram, ages that are more than 10% discordant were excluded There is a peak at ca. 3200 Ma matching the age of the Santa together with spot analyses with Th/U < 0.1. Detrital zircon grains Barbara event; from the volcaniclastic graywackes of the Nova Lima Group define a The ca. 3000 Ma peak suggest an event of continental crust polymodal age spectrum with ages ranging from 2700 to 3450 Ma. production that took place between the Rio Das Velhas I and The occurrence of a large number of detrital zircon grains suggests Santa Barbara magmatic events; that these rocks were not formed in an intra-oceanic arc environ- Small peaks at ca. 3450 and 3550 Ma were found by Noce et al. ment, but more likely in an intra-continental or continental-margin (2005) and Machado et al. (1996), respectively. The age of these tectonic setting (Noce et al., 2005). When the age distribution of peaks do not match with any of the magmatic event preserved detrital zircons in the Nova Lima Group is compared with the age of in the basement, suggesting the existence of a pre-3200 Ma the main magmatic events defined by Lana et al. (2013), Romano (older than the Santa Barbara event) continental crust. et al. (2013) and Farina et al. (2015a), the following observations 12 F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21

further subdivided into:

A ca. 600 m-thick package of gold-uranium-bearing alluvial to marine sandstones, conglomerates and subordinate offshore pelites comprising the Tamandua and Caraça groups (Simmons and Maxwell, 1961; Dorr, 1969). These rocks represent the rift and transitional phases of the passive margin development (Renger et al., 1995; Alkmim and Marshak, 1998); A 400 m-thick package of marine sediments that includes banded iron formations and carbonates of the Itabira Group (Dorr, 1969), recording the thermal subsidence stage of the continental passive margin (Alkmim and Marshak, 1998); A ca. 450 m-thick pile of deltaic to shallow marine to deep water sediments (Piracicaba Group, Renger et al., 1995), consisting mainly of siliciclastic rocks with minor carbonates.

In the next sections, we will present the main stratigraphic and geochronological features of each group. A summary of ages for the Fig. 9. Frequency histogram showing the age distribution of detrital zircon grains in Minas Supergroup is presented as Supplementary material the rocks of the Rio das Velhas Supergroup. The probability curve is produced (Table D). considering 109 UePb analyses from Machado et al. (1992); Machado et al. (1996); Noce et al. (2005); Hartmann et al. (2006). Maximum discordance accepted 10%. An- 6.2. Tamandua and Caraça Groups alyses with Th/U < 0.1 were excluded. Vertical bands mark the age of the main magmatic events in the basement. The beginning of the rifting stage is recorded by the deposition of the Tamandua Group and by the overlying basal unit of the The limited available UePb age data for the Maquine Group Caraça Group: the Moeda Formation (Dorr, 1969). The Tamandua suggest that a continental block ranging in age from 3260 to Group (Simmons and Maxwell, 1961; Dorr, 1969) comprises mostly 2877 Ma was the main source for the sandstones and conglomer- quartzites, quartzose and argillaceous schists -also referred as ates of this group (Machado et al., 1996). A recent study has asso- Cambotas Quartzite- and minor phyllitic and dolomitic itabirites at ciated this sedimentary sequence with the genesis of an inferred the top. The unit crops out in small and discontinuous areas, lying arc formed during the Rio das Velhas II event (Lana et al., 2013). in contact with the Maquine Group through an erosional uncon- Moreira and Lana (2015) produced geochronological UePb data of formity (Dorr, 1969). The absence of well-preserved sedimentary ca. 1500 zircon grains from different units of the Maquine Group. structures or marker beds hinders possible correlations between The new data indicate that the main source of the basin are rocks this group and other similar deposits within the Quadrilatero formed between 2760 and 2800 Ma (i.e. Rio das Velhas II event) and Ferrífero. that the maximum depositional age for the Casa Forte Formation is The Caraça Group (Dorr, 1959) is a blanket deposit, having great 2730 Ma. Thus, suggesting that the basin closed after the Mamona lateral extension compared with its average thickness. It encom- magmatic event. passes metasedimentary quartzitic rocks (Moeda Formation) and Finally, Schrank and Machado (1996a,b) dated monazite grains phyllites (Batatal Formation) that conformably underlie the from the Nova Lima and upper Maquine Groups obtaining Paleo- chemical sediments of the Itabira Group, and commonly overlie proterozoic metamorphic ages spanning between 2080 Ma and with angular and erosional discordance the rocks of the Archean 1989 Ma (Table E, Data Repository). These data are consistent with greenstone belt. The Moeda Formation comprises mostly quartzites the ages obtained for metamorphic monazite and titanite grains and minor basal pyritiferous metaconglomerates, locally auriferous from the basement (Noce et al., 1998; Aguilar et al., 2015)aswellas cropping out predominantly in the western part of the Quadrilatero with UePb zircon magmatic ages from two leucocratic dikes ana- Ferrífero (Dorr, 1969; Vilaça, 1981; Renger et al., 1988; Koglin et al., lysed by Machado et al. (1992) in the southern part of the Baçao~ 2012). The average thickness of the formation is ca. 300 m, locally complex. reaching up to 1000 m. This sequence represents a braided river system locally alternated with deltaic to beach deposits as well as 6. The Minas Supergroup with thin deposits formed during marine transgression events (Vilaça, 1981; Canuto, 2010). The Moeda Formation exhibits sig- 6.1. Main stratigraphic features nificant mineralogical and grain size lateral variation. In several localities, the basal conglomerates exhibit lenticular shaped peb- The Paleoproterozoic Minas Supergroup (Dorr, 1969; Babinski bles and cobbles of phyllites probably from the Nova Lima Group as et al., 1991; Renger et al., 1995) is a ca. 6000 m-thick package of well as rounded quartz and quartzite cobbles (Dorr, 1969; Koglin clastic and chemical rocks (Alkmim and Marshak, 1998) lying un- et al., 2012). Some of the basal fluvial metaconglomerates exhibit conformably on the Archean greenstone belt (Fig. 2). Following heavy mineral layers of detrital pyrite with economic gold con- Alkmim and Martins-Neto (2012), the Minas Supergroup can be centrations (Renger et al., 1988). The Caraça cycle ends with the subdivided in two sequences separated by a regional unconformity. deposition of the Batatal Formation (Maxwell, 1958; Dorr, 1969) The basal sequence, involving continental to marine sediments that conformably overlies the Moeda Formation. The contact be- (Dorr, 1969; Renger et al., 1995) represents the development stage tween the two formations is commonly sharp, but locally the units of a passive margin basin (Schorscher, 1992; Canuto, 2010). The can also be intergradational (Wallace, 1965). The Batatal formation overlying sequence, consisting of the turbidites of the Sabara Group consists of bluish-grey phyllites with minor metacherts, iron- was interpreted as a submarine fan deposit marking the inversion formation and graphitic phyllites (Simmons, 1968) cropping out of the passive margin (Alkmim and Marshak, 1998). in the western and central areas of the Serra do Curral where it The basal continental to marine sedimentary sequence has been shows a thickness ranging from 30 to 200 m (Dorr, 1969). The F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 13 sedimentation of the Batatal Formation reflects the transition to- from the Gandarela syncline. This age, due to the preservation of wards a marine to coastal marine environment (Moraes, 1985), organic structures and the absence of deformation in the rocks of registering the passage from the rift-opening stage to the passive the Ganderela Formation, is considered to represent the sedimen- margin stage (Alkmim and Marshak, 1998). tation age of the carbonates. Zircon UePb detrital age data for the quartzites of the Caraça The age of deposition of the Caue^ Formation was conservatively and Tamandua sediments show two main age populations: bracketed between 2620 and 2420 Ma; i.e. between the maximum 2.85e2.90 and 2.68e2.75 Ga (Machado et al., 1996; Hartmann et al., age of deposition of the top of the underlying Moeda Formation 2006; Koglin et al., 2014, Fig. 10). The age of these population peaks (Koglin et al., 2014) and the age of the overlying Gandarela For- matches with the Rio das Velhas I and Mamona events for the mation (Babinski et al., 1995). Recently UePb dating of zircon grains genesis of the gneisses and granites of the basement. The youngest from a metavolcanic layer sampled within the Itabira iron forma- concordant zircon detrital age for a quartzite sample of the Tam- tion led Cabral et al. (2012) to propose a considerably earlier andua Group indicates a maximum age of sedimentation of (2650 Ma) deposition age for this unit (Fig. 10). The interpretation 2676 ± 23 Ma (Koglin et al., 2014). The deposition age for the Moeda of this age is controversial, since it contradicts most of the data Formation is a matter of debate. A maximum depositional age as produced so far for the underlying Caraça Group. Recently, LA-ICP- young as 2580 ± 7 Ma was proposed by Hartmann et al. (2006) MS UePb dating of detrital zircon grains from a quartzite lens based on UePb SHRIMP data from a zircon grain derived from a hosted within the Caue^ Formation showed a quasi-unimodal dis- quartzite at the top of the Serra de Moeda. This maximum age of tribution with a peak at 2795 Ma (Cassino et al., 2014; Martínez sedimentation is slightly younger than the deposition ages deter- Dopico et al., 2015). The youngest concordant zircon grain in this mined by Machado et al. (1996) for three quartzites collected near lens yielded an age of 2453 ± 18 Ma. the city of Ouro Preto, south of the Serra do Gandarela and in western flank of the Serra de Moeda (2606 ± 47 Ma, 2649 ± 16 Ma 6.4. Piracicaba Group and 2651 ± 33 Ma, respectively). Recently, UePb analyses carried out on zircons grains from the southernmost tip of the Serra de The carbonates of the Gandarela Formation are in contact with Gandarela led Koglin et al. (2014) to re-establish a maximum deep-seated marine sandstones and pelites of the Piracicaba Group depositional age for the upper part of the Moeda Formation of (Dorr et al.,1957; Dorr, 1969). This group is composed of ca. 1300 m- 2623 ± 14 Ma. In addition, Koglin et al. (2014) determined the thick metasediments consisting of quartz-rich sandstones that LueHf isotope composition of detrital zircon grains from meta- gradually fines and thins upward to mudstone and graphitic conglomerates of the Moeda Formation. The zircon grains show mudstone. The Piracicaba Group is subdivided into four formations ^ ~ mainly subchondritic initial εHf and large εHf variations for all the that are known as the Cercadinho, Fecho do Funil, Tabooes and population peaks described by Koglin et al. (2014). Barreiro formations (Fig. 3). The lowest sequence (i.e. Cercadinho Formation) comprises coarse to fine grained hematite-rich 6.3. Itabira Group quartzites, quartzites, silvery sheen phyllites, Fe-rich phyllites as well as dolomites (Simmons, 1968; Dorr, 1969). A conglomerate The sedimentation of the Caraça shallow-water pelites (Batatal containing pebbles derived from the underlying Caue^ and Gan- Formation) is interdigitated with rocks formed during a major darela Formations, from which the Cercadinho Formation is sepa- marine transgression recording a period of iron-rich chemical rated by an erosional unconformity, marks the base of the sedimentation known as the Itabira Group (Dorr, 1969). This event Piracicaba Group. led to the accumulation of more than 350 m-thick Lake Superior- Detrital zircon grains from quartzites and poorly sorted type banded-iron deposit ethe Caue^ Formation (Fig. 8d)-, and to conglomeratic quartzites at the base of the Cercadinho Formation, the subsequent deposition of ca. 600 m of the stromatolite-rich in the western part of Serra do Curral, show an Archean contribu- carbonates of the Gandarela Formation (Fig. 3; Dorr, 1969; tion during the initial stages of deposition of the Piracicaba Group Babinski et al., 1995; Machado et al., 1996). The Caûe Formation (Mendes et al., 2014). The detrital zircon ages from these samples (Dorr, 1969; Klein and Ladeira, 2000) or Caue^ Itabirite eas meta- range between 2750 and 2900 Ma with two distinguishable peaks morphosed rocks of the banded iron-formations are known in at 2793 Ma and 2859 Ma (Fig. 10), which correspond to the Rio das Brazil - is nowadays the economically most important unit of the Velhas II and Rio das Velhas I events. The deposition age for the Quadrilatero Ferrífero, hosting world-class hematite-rich iron ore Piracicaba Group is still poorly constrained between 2420 Ma (i.e. deposits producing more than 180 Mt per year (Rosiere et al., 2008). the age of the Gandarela Formation; Babinski et al., 1995) and ca. Three compositionally different lithofacies of the metamorphosed 2100 Ma (Babinski et al., 1993). The lowest age of deposition for the iron formations exist: quartzitic itabirite, dolomitic itabirite and the Piracicaba Group (2100 Ma) was obtained by Babinski et al. (1993) volumetrically minor amphibolitic itabirite. Rosiere et al. (2008) dating deformed dolomitic carbonates from the Fecho do Funil reviewed the main features of the iron ores in the Quadrilatero Formation. This Pb/Pb isochron age is interpreted as the meta- Ferrífero, presenting the petrogenetic and metallogenic models morphic age of the rock, thus defining the minimum age of depo- proposed for the origin of these rocks. The youngest unit of the sition for the carbonates. Itabira Group is the Gandarela Formation (Dorr, 1969; Babinski et al., 1993). This formation is predominantly composed of dolo- 6.5. Sabara Group mites, limestones, carbonaceous phyllites and dolomitic iron-rich formation in which stromatolitic structures are preserved (Souza The Sabara Group is the youngest and thickest unit of the Minas and Müller, 1984). This formation crops out in the Serra de Supergroup (Fig. 2), comprising up to 3.5 km-thick pile of coarsening Moeda, in the central part of the Serra do Curral and in the Gan- upwards sequences of metapelites, greywackes, lithic conglomerates darela syncline where it reaches its maximum thickness (750 m, (Fig. 8e), and diamictites (Dorr, 1969; Barbosa, 1979; Renger et al., Dorr, 1969). Its basal contact with the Caûe Formation consists of a 1995; Reis et al., 2002). This formation is interpreted as represent- transitional zone (up to ten meters thick) in which the dolostone is ing a turbiditic, submarine fan deposit formed during the inversion associated with the dolomitic itabirite. Babinski et al. (1995) pro- of the Minas Supergroup passive margin (Alkmim and Martins-Neto, vided an isochron PbePb age of 2419 ± 19 Ma for a stromatolithic 2012). The unit is well exposed and can be mapped continuously for limestone from an intermediate member of the formation sampled more than 60 km along the Serra do Curral (Fig. 1). 14 F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21

Fig. 10. Frequency histogram for the Minas Supergroup. Histograms and Probability Density plots for the available UePb zircon ages of the Minas Supergroup and Itacolomi Group. Age display software (Sircombe, 2004) was used to build the graphs and evaluate the data. All weighted zircon data was 95% concordant (excepting data from Machado et al., 1996) and treated as sigma-1 errors. F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 15

Detrital zircon ages obtained by Machado et al. (1996) for a precision. However, the database of Hartmann et al. (2006) is very greywacke from the Serra do Curral suggest a distinctive age dis- limited and likely not representative as these authors analysed only tribution pattern showing a few Proterozoic ages spreading be- seven concordant zircons. Hartmann et al. (2006) determined a tween 2100 and 2500 Ma and a well-defined peak at maximum depositional age of 2143 ± 16 Ma for the Itacolomi Group 2850e2900 Ma (Fig. 10). The UePb age distribution of detrital in its type locality while Machado et al. (1996) determined depo- zircon grains in this sample is remarkably different from the age sitional ages that are ca. 100 Ma younger (i.e. 2039 ± 42 Ma and distribution of zircon grains from a felsic schist belonging to the 2059 ± 58 Ma; Fig. 10). Another difference between the two data- Sabara Group, collected close to Ouro Preto. The schist, analysed by sets is that Machado et al. (1996) found many grains yielding Hartmann et al. (2006) by SHRIMP, shows no Proterozoic ages and 207Pb/206Pb ages in the range 2200e2500 Ma (Fig. 10) which were two Archean peaks at 2720 and 2900 Ma (Fig. 10). Although, not found by Hartmann et al. (2006). Finally, in contrast to what is Hartmann et al. (2006), reported no Proterozoic ages, a Rhyacian observed for the underlying Sabara Group, only a subset of zircon maximum age of deposition for the Sabara Group is confirmed by grains from the sandstone and conglomerates of the Itacolomi two zircon ID-TIMS UePb ages yielding 2125 ± 4Ma(Machado Group yielded Archean ages. The large percentage of Rhyacian et al., 1992) and 2131 ± 5Ma(Machado et al., 1996). These Rhya- detrital zircons (i.e. between 2300 and 2050 Ma) in the conglom- cian ages match well with the ages obtained by Noce et al. (1998) erates of the Itacolomi basins support a non-cratonic source and Seixas et al. (2013) from the Alto Maranhao~ suite (ca. (Machado et al., 1996; Alkmim and Marshak, 1998) suggesting that 2130 Ma) and associated granitoids of the Mineiro Belt most of the sediments were derived from terrains generated during (2100e2200 Ma) that bounds the Quadrilatero Ferrífero to the the Rhyacian orogeny. The source was probably located to the south south. In addition, the deposition of the Sabara turbidites marks a and southeast, with the Alto Maranhao~ Suite (ca. 2130 Ma, Seixas, major change in the source of Minas sediments. Paleogeographic et al., 2013), Juiz de Fora (2041 ± 7 Ma and 2137 ± 19, Noce et al., studies (Dorr, 1969; Renger et al., 1995; Machado et al., 1996) 2007) and Mantiqueira complexes (2119 ± 16 to 2084 ± 13 Ma, indicate that during the genesis of the passive margin the Archean Noce et al., 2007) being the most suitable candidates. The Itacolomi sources were located to the north. On the other hand, a non- Group is interpreted as an intermontane molasse deposit devel- cratonic source, located to the south and southeast, is suggested oped along the margin of the Archean nucleus of the Sao~ Francisco to account for the occurrence of 2100 Ma old granitoid clasts and craton during the collapse phase of the Rhyacian orogeny (Marshak zircons in the conglomerates of the Sabara Group (Alkmim and et al., 1992; Alkmim and Marshak, 1998; Alkmim and Martins-Neto, Martins-Neto, 2012). The turbiditic pelites, greywackes, lithic con- 2012). glomerates and diamictites of the Sabara Group were interpreted as representing syn-orogenic sediments (Dorr, 1969; Renger et al., 8. Mafic and intermediate dikes, boudins and lenses 1995; Reis et al., 2002) shed from a colliding magmatic arc and spread over an evolving foreland basin onto the Sao~ Francisco Mafic and intermediate amphibolites in the Quadrilatero Ferrí- craton margin during the Rhyacian orogeny (Alkmim and Martins- fero crop out as meter-scale blocks, boudins and lenses hosted Neto, 2012). within the gneisses as well as dikes crosscutting granites and Supracrustal rocks. Carneiro (1992) and Carneiro et al. (1998) 7. The Itacolomi Group defined four groups of mafic-intermediate amphibolites in the Bonfim complex, based on field relationships, trending directions The Itacolomi Group (Dorr, 1969), the youngest unit in the as well as on textural and compositional data. Two swarms of dikes Quadrilatero Ferrífero supracrustal sequence, comprises an up to crosscut the basement and give Neoarchean SmeNd model ages 2 km-thick section of medium-to coarse-grained impure meta- (Carneiro et al., 1998) while the other two groups are younger as sandstones, metaconglomerates and minor phyllites separated suggested by the fact that they crosscut Paleoproterozoic meta- from the underlying Minas Supergroup by a low-dipping regional sediments and exhibit well-preserved igneous textures. In the Belo unconformity (Dorr, 1969; Alkmim and Martins-Neto, 2012). The Horizonte Complex, unmetamorphosed tholeiitic dikes crosscut- occurrence of a major erosional event at the base of the unit is ting the basement and the Supracrustal sequences yielded K/Ar manifested by the polymictic nature of the metaconglomerates, in feldspar ages of ca. 1000 Ma (Chaves, 1997). These dikes, related to which pebbles of quartzite, itabirite and granitic rocks were the separation between the Sao~ Francisco and the Congo cratonic recognized (Dorr, 1969). The group has a restricted areal distribu- blocks in the Late Mesoproterozic (De Min et al., 2005), will not be tion, limited to the southernmost region of the Quadrilatero Fer- described any further as this late evolution of the Quadrilatero is rífero south of Ouro Preto (Fig. 1). These rocks preserve primary beyond the scope of this review. sedimentary structures such as ripple marks and crossbedding and The oldest population of amphibolites in the Quadrilatero is exhibit abrupt lateral changes of sedimentary facies (Fig. 8f). These composed of mafic and intermediate rocks that intruded as dikes features suggest that the Itacolomi Group represents interfingering and were later strongly rotated and disrupted, appearing now as marine and continental deposits. The only studies of sedimentary boudins and lenses within the enclosing gneisses. These boudins or provenance that used UePb dating of detrital zircons for the Ita- lenses (hereafter “rafts”) are fine-to medium-grained, with textures colomi Group are those published by Machado et al. (1996) and varying from nematoblastic to granoblastic and geochemistry of more recently, Hartmann et al. (2006). A summary of zircon UePb within-plate tholeiitic basalts. Recently, one of these rafts from the ages in the Itacolomi Group is presented as Supplementary material Baçao~ complex was dated by zircon UePb geochronology by Lana (Table D). The two datasets show significant differences that are et al. (2013) yielding a well-defined Concordia age of difficult to reconcile as the datasets are hardly comparable. 2778 ± 8 Ma. Titanite UePb ages from the same mafic raft yield Machado et al. (1996) determined by laser ablation the UePb age of Paleoproterozoic (ca. 2100 Ma) ages suggesting resetting of the many detrital grains, however the age uncertainties are variable basement in the southern Quadrilatero during the Rhyacian and typically large (1s ¼ 15e200 Ma) and the degree of concor- (Aguilar Gil et al., 2015). Farina et al. (2015a) dated a dike cross- dance is not provided, therefore casting doubt about the reliability cutting the ca. 2770 Ma old Samambaia tonalite in the Bonfim of these ages. On the other hand, Hartmann et al. (2006) used a dome. Zircon grains from this rock gave a weighted mean more accurate technique (SHRIMP) and provided information 207Pb/206Pb age of 2719 ± 14 Ma, with this age matching well with about the degree of concordancy as well as on accuracy and the age of the oldest mafic dikes in the Uaua block in the northern 16 F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21

Sao~ Francisco craton (i.e. 2726.2 ± 3.2 Ma; Oliveira et al., 2013). show normal sense kinematic indicators (Hippertt et al., 1992), These geochronological data seem to confirm the occurrence of two while the shear sense observed in the contact zone of the Baçao~ and Neoarchean systems of dikes. The first swarm that emplaced at ca. Caete domes varies between reverse, reverse-oblique and strike- 2780 Ma was successively metamorphosed and deformed together slip (Marshak and Alkmim, 1989; Hippertt, 1994; Endo, 1997). Ki- with the hosting gneisses. The second population of dikes crosscuts nematic indicators in supracrustal rocks clearly indicate granitoids formed during the 2760e2680 Ma Mamona event. These supracrustal-side-down displacement (Marshak et al., 1997) sup- dike systems are useful relative time markers allowing bracketing porting an extensional event (Hippertt et al., 1992). Metamorphic of the metamorphism and deformation between 2780 Ma and aureoles in the supracrustal rocks at the contact with the domes 2720 Ma. The tectonic significance of these Archean dikes is have different thickness (Pomerene, 1964; Herz, 1978; Carneiro and currently unknown as no systematic geochemical and isotopic Teixeira, 1992; Jordt-Evangelista et al., 1992; Marshak et al., 1992, studies were attempted. 1997). The dome-border shear zones and their related meta- morphic aureoles overprint the foliation of Archean gneisses as 9. Main structures and structural evolution well as the early regional lower greenschist-facies metamorphism and the foliation, folds and faults in the supracrustal sequence. This The Quadrilatero Ferrífero experienced a polyphase tectonic evidence indicates that the doming event post-dated the history that produced complex regional patterns of rock deforma- northwest-verging thrust and associated syncline folds (Marshak tion (e.g., Dorr, 1969; Drake and Morgan, 1980; Endo, 1997; Alkmim et al., 1992; Alkmim and Marshak, 1998). Synkinematic garnets and Marshak, 1998; Chemale et al., 1994; Chauvet et al., 1994). This formed in a dome-border shear zone in rock of the Minas Super- complexity, together with the lack of absolute ages dating the group gave a SmeNd age of 2095 ± 65 Ma (Marshak et al., 1997). tectonic structures, gave rise to different and in many cases con- This age, that is consistent with titanite and monazite UePb flicting interpretations for the deformation history of the Quad- metamorphic ages obtained in the basement (Machado et al., 1992; rilatero. Three main sets of structures characterise the Quadrilatero Schrank and Machado, 1996a,b; Aguilar et al., 2015), suggests that Ferrífero; from the oldest to the youngest, these are: dome emplacement occurred during the extensional collapse of the Rhyacian orogen. - Northwest-verging and northenortheast-trending regional- Finally, the collisional and extensional structures described scale folds and thrusts generating large asymmetric synclines were overprinted and reactivated by a series of west-verging thrust (the Moeda, Dom Bosco, Pitangui-Peti, Mateus Leme and Souzas faults and associated structures, attributed to the Neoproterozoic to folds) and the steeply dipping to overturned Serra do Curral Early Ordovician Brasiliano event (650e480 Ma; e.g., Endo and homocline (e.g., Pomerene, 1964; Dorr, 1969; Pires, 1979; Fonseca, 1992; Chemale et al., 1994; Alkmim and Marshak, 1998). Marshak et al., 1992; Alkmim and Marshak, 1998, Fig. 1); - Extensional structures related to the formation of a typical 10. Discussion: models and open problems dome-and-keel province, in which troughs of deformed and metamorphosed Paleoproterozoic supracrustal rocks surround This section is subdivided into five paragraphs; in the first four domes of Archean basement (e.g., Belo Horizonte, Caete, Baçao~ we discuss the evolution of the Quadrilatero Ferrífero from the complexes; Chemale et al., 1991, 1994; Alkmim and Marshak, genesis of the continental crust in the Paleoarchean to the Paleo- 1998); proterozoic Minas orogeny. In the last paragraph, we present a - West verging thrust folds reactivated and overprinted pre- series of unresolved questions relative to the genesis and evolution existent structures in the region east of a north-trending line of the Quadrilatero Ferrífero. that follows the west edge of the Moeda syncline (Fig. 1; Chemale et al., 1994); 10.1. Building up the continental crust: the Paleo-to Mesoarchean rock record According to Alkmim and Marshak (1998), these structures correspond to three kinematic phases that affect the rocks of both The oldest preserved rocks in the Quadrilatero Ferrífero are the Rio das Velhas and Minas Supergroups. The maximum age of banded gneisses from the Santa Barbara complex that formed at the formation of the oldest structures is constrained by the deposition Paleo-Mesoarchean boundary (i.e. 3200 Ma, Lana et al., 2013). age of the top of the Minas Supergroup: the Sabara group. This Unfortunately, very little study has been conducted on these rocks 3.5 km-thick flysch sequence that has a maximum deposition age of so the Paleo-Mesoarchean rock record of the Quadrilatero Ferrífero 2130 Ma (Machado et al., 1996) is involved in northwest-verging remains enigmatic. Although the presences of these gneisses, folding. This age constraint led Alkmim and Marshak (1998) to despite being extremely rare in the rock record, provide various interpret the northwest-verging folds and thrusts as a fold and lines of evidence to suggest that a significant volume of continental thrust belt formed shortly after the deposition of the Sabara Group crust formed during the Paleoarchean and in the late Mesoarchean in the foreland of a Rhyacian collisional orogeny. Regional lower-to (Lana et al., 2013). Firstly, zircon ages yielding 3000e3400 Ma ages high-grade metamorphism affecting the Minas Supracrustal rocks occur as inherited components in a limited number of gneisses is associated with the northwest-verging folds. The metamorphic dated by Lana et al. (2013) and represent a significant subset in the grade increases eastward from the Bonfim to the Baçao~ complexes, detrital spectra of the greenstone belt succession and the Minas reaching granulite-facies in the easternmost part of Quadrilatero Supergroup (Figs. 9 and 10). In particular, minor peaks at ca. Ferrífero (Herz, 1978; Gomes, 1986; Gomes and Muller, 1987). This 3200 Ma occur in the Tamandua, Caraça, Itabira and Piracicaba event, however, did not generate a strong foliation. Groups (Fig. 10) as well as in the greenstone belt in both the Nova The second structures relate to the formation of the dome-and- Lima (Fig. 9) and Maquine groups (Moreira and Lana, 2015). Sec- keel geometry of the Quadrilatero. The contacts between gran- ondly, SmeNd model ages for Neoarchean gneisses and granites in iticegneissic complexes and the Supracrustal sequences are tec- the Bonfim complex gave values up to 3300 Ma (Teixeira et al., tonic, marked by thrusts and/or normal faults, and by ductile shear 1996). Finally, most of the detrital zircons from the Moeda, Caue^ zones showing variable sense of displacement (Hippertt et al.,1992; and Piracaba formations have subchondritic initial εHf values Machado et al., 1996; Alkmim and Marshak, 1998). For instance, the resulting in calculated depleted mantle model ages varying from enveloping shear zones of the Bonfim and Belo Horizonte domes 3000 to 3800 Ma (Koglin et al., 2014; Martínez Dopico et al., 2015). F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 17

These model ages are in good agreement with those calculated by Baçao,~ Bonfim and Belo Horizonte complexes (Machado et al., 1992; Albert et al. (2015) for magmatic zircons in gneisses and granitoids Romano et al., 2013; Farina et al., 2015a). During these ca. 50 Ma of from the Bonfim complex. Taken together these geochronological metamorphism the medium-K granitoids were deformed and and isotopic data advocate for the existence in the Quadrilatero transformed into banded gneisses and leucogranitic sheets and Ferrífero of a large segment of Paleoarchean continental crust that mafic/intermediate dikes were emplaced and rotated into paral- was reworked during successive pulses of magmatic activity and lelism with the banding in the gneisses. The pressure and tem- eroded during tectonic denudation. perature conditions attained during the metamorphic event are not Recently, Farina et al. (2015a) compared the composition of constrained, but the occurrence of migmatites formed by fluid- gneisses and granitoids from the Quadrilatero Ferrífero with TTGs present melting of the gneisses suggests that the basement from other cratons and experimental melts produced by fluid- locally reached upper amphibolite-facies conditions (Farina et al., absent melting of tonalites. Medium-K rocks are significantly 2015b). We suggest that this high-grade metamorphic event re- more silica- and K2O-rich and less Na2O- and Al2O3-rich than cords the collision between two continental blocks. During crustal typical TTGs (Fig. 5) and show intermediate compositions between thickening, part of the metasedimentary pile were stacked, TTGs and experimental melt obtained through fluid-absent partial deformed and buried. Then, thermal relaxation and extension melting of TTG sources such those used as starting material by following lithospheric delamination triggered the upwelling of the Watkins et al. (2007). Based on whole-rock chemical arguments, asthenosphere heating up the continental crust and inducing par- Farina et al. (2015a) suggested that medium-K banded gneisses and tial melting. High-K granites and crosscutting mantle-derived dikes granitoids formed by mixing between a TTG-like melt produced by forms in this syn-to late-collisional geodynamic environment. partial melting of basaltic oceanic crust and a melt derived by Based on whole-rock chemical arguments, Farina et al. (2015a) reworking of the continental crust. The occurrence of a recycled suggested that high-K granites in the Quadrilatero were produced crustal component in the genesis of the medium-K rocks formed by low degree of melting of metasedimentary sources deposited during the Rio Das Velhas I and II magmatic events is supported by during the Rio das Velhas II event. In this scenario, the transition the negative εHf composition displayed by both detrital zircons in between medium-K and high-K granitoids reflects a change in the the Moeda and Piracicaba formations (Koglin et al., 2014; Martínez sources undergoing melting. Dopico et al., 2015) and magmatic zircon crystals in gneisses and It is worth noting that during the Neoarchean the northern (the granitoids (Albert et al., 2015). A subset of detrital zircon in the Belo Horizonte Complex) and southern (the Baçao~ and Bonfim Moeda Formation (<10% of the grains) and magmatic zircon from a complexes) portions of the Quadrilatero Ferrífero experienced few gneisses sampled in the Baçao~ complex show superchondritic different magmatic evolutions. In the southern portion, medium-K Hf isotopic compositions suggesting that juvenile crust was also granitoids emplaced for ca. 20 Ma (2790e2770 Ma) after the formed during the Meso- and Neoarchean Rio das Velhas I and II metamorphic peak and were then replaced by high-K mon- magmatic events (Koglin et al., 2014; Albert et al., 2015). zogranite and syenogranite with composition of late Archean bio- tite and two-mica granites (Farina et al., 2015a,b). This rather sharp 10.2. The record of plate tectonics: the Meso-Neoarchean compositional change was not recorded in the Belo Horizonte complex where the ca. 2750e2720 Ma massive granitic batholiths Two significant changes occurred in the Quadrilatero Ferrífero (Pequi and Florestal, Fig. 1) have TTG-affinity. In the Belo Horizonte during the early Neoarchean, between ca. 2800 and 2700 Ma. Complex, minor bodies of high-K granites (e.g. the Santa Luzia Firstly, high-K granites similar to post-Archean high-silica I-type Granite) were only emplaced at ca. 2700 Ma (Noce et al., 1997). granites were produced, largely replacing medium-K granitoids The emplacement of high-K granites during the Mamona and gneisses; the latter showing chemical affinity similar to TTGs magmatic event marks the final cratonization of the Quadrilatero and representing the volumetrically dominant rocks produced Ferrífero, which remained stable from ca. 2700 Ma onwards. This during the Rio das Velhas I and II events (ca. 2920e2760 Ma). probably occurred because the emplacement of high-K magmas at Secondly, mature sedimentary sequences emerged and were shallow level in the crust concentrated heat-producing elements deposited in the Rio das Velhas greenstone belt forming the (e.g. K, Th, U) in the upper crust, leaving the middle crust thermally 2000 m-thick association of conglomerates and sandstones of the stable (e.g. Sandiford and McLaren, 2002). In addition, partial Maquine Group. We argue that a model involving subduction of melting of the continental crust left the lower crust dry (refractory) oceanic crust and subsequent continental collision between two and therefore more resistant to future episodes of partial melting continental blocks account for these two major changes explaining (Romano et al., 2013). coherently most of the Neoarchean evolution of the Quadrilatero Ferrífero. The model that is illustrated in Fig. 11 has been proposed 10.3. Evolution of the Minas Basin to explain the late-Archean geodynamic evolution of many other terranes worldwide (e.g., Percival et al., 2006; Laurent et al., 2014). The rocks of the Minas Supergroup represents a passive-margin In the Quadrilatero, medium-K rocks were produced during the to syn-orogenic sedimentary package tracking the operation of a Rio das Velhas I and II events (2920e2850 and 2800e2760 Ma). Wilson cycle between ca. 2.6 and 2.0 Ga (Schorscher, 1992; Alkmim These rocks have chemical composition suggesting mixing be- and Marshak, 1998; Canuto, 2010). The development of the Minas tween magmas derived by partial melting of an oceanic crust and passive margin took place in the time interval between approxi- magmas derived by crustal reworking. These compositions can be mately 2600 and 2400 Ma (i.e. between the deposition of the generated by significant interaction between melts derived by Moeda and Gandarela formations; Babinski et al., 1995; Koglin melting a subducting oceanic slab and an upper plate formed by a et al., 2014) along the borders of the Sao~ Francisco and Congo Meso- Paleoarchean continental nucleus. In this scenario, clastic cratons. The clastic metasedimentary rocks, which form the lower sediments from the upper-plate eroded and deposited in a back arc part of the Minas Supergroup (the Tamandua and Caraça groups), basin (i.e the Maquine Group) and volcanic rocks with TTG-affinity were deposited during the early subsidence of the precursor erupted forming dacitic flows in the greenstone belt. Archean passive margin basin. The intermediate Itabira Group that The granitoids formed during the Rio das Velhas II event were is composed of the Caue^ Banded Iron Formation, hosting the readily deformed and metamorphosed between 2780 and 2730 Ma valuable iron ore deposits of the Quadrilatero Ferrífero, and of the as indicated by the age of the earliest granites emplaced in the limestones of the Gandarela Formations, mark the thermally 18 F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21

Fig. 11. Sketch of the geodynamic evolution of the Quadrilatero Ferrífero during the Rio Das Velhas I, Rio Das Velhas II and Mamona periods. In the 2920e2850 Ma cartoon, we tentatively propose that the continental crust formed by multiple accretion of island-arcs. During the Rio das Velhas II period, the subduction of an oceanic crust under a continental block led to the formation of medium-K granitoids by mixing between two components: melts derived by partial melting of the mafic oceanic crust and melts derived by recycling of older continental crust. During this event, volcanic rocks erupted above the ultramafic-mafic sequence of the Nova Lima Group and mantle-derived magmas intruded the basement. Finally, during the Mamona event, two continental blocks collided. Slivers of metasediments were buried and started melting producing high-K granites and clastic sediments were deposited forming the Maquine Group. Based on an illustration from Laurent (2012). subsiding stage of the Minas Basin (Alkmim and Martins-Neto, northenortheast-trending regional-scale folds and thrusts with 2012). Finally, clastic immature and flysch-like metasedimentary associated low-to medium-grade metamorphism affecting the rocks of the uppermost Sabara Group, marks the inversion of the supracrustal rocks and ii) gneiss-granitic domes surrounded by basin representing syn-orogenic sediments shed from a colliding elongate keels of polydeformed supracrustal rocks (i.e dome-and- magmatic arc (Dorr, 1969; Barbosa, 1979; Renger et al., 1995). The keel structure). These structures formed in the Paleoproterozoic Sabara Group contains detrital zircon grains as young as as indicated by the depositional age of the Sabara Group (2125 Ma; 2125 ± 4Ma(Machado et al., 1992); i.e. 300 Ma younger than the Machado et al., 1996), which is involved in the folding and age of the underlying units of the Minas Supergroup. This marks a thrusting, as well as by the age of the dome-related metamorphic significant change in both the depositional setting and sediment contact aureole (ca. 2095 Ma; Marshak et al., 1997). The fold-and source compared to the older Minas units that mainly derived from thrust belt formed in the Paleoproterozoic during the collision Archean material. The Sabara turbidites are a submarine fan deposit between the nuclei of the present-day Sao~ Francisco and Congo interpreted as having formed either as a syn-orogenic deposit cratons (Alkmim and Martins-Neto, 2012). In the southern portion scraped off from an active magmatic arc (Hartmann et al., 2006)or of the Sao~ Francisco craton, the continental collision between these as a foreland basin (Machado et al., 1996). two plates generated the Mineiro Belt and the adjoining Man- tiqueira and Juiz de Fora belts (Teixeira et al., 2015). The Mineiro Belt, bordering the Quadrilatero Ferrífero to the south, is a km-wide 10.4. The Minas accretionary orogeny corridor of polydeformed Archean gneisses and greenstone belt remnants intruded by 2350e2000 Ma granitoids (Seixas et al., The regional setting of the Quadrilatero Ferrífero is dominated 2012). This belt was generated through successive accretion of by two set of structures: i) northwest-verging and F. Farina et al. / Journal of South American Earth Sciences 68 (2016) 4e21 19 oceanic and continental arcs that were active during the Paleo- What is the age of the mafic and ultramafic rocks in the Rio das proterozoic and then final collision with the Sao~ Francisco craton, Velhas Supergroup? What is the age of the greenschist facies representing the foreland of the belt (Teixeira et al., 1996; Alkmim metamorphism of the Rio das Velhas Supergroup? What is the and Marshak, 1998; Avila et al., 2010). This event is recorded in the tectonic significance of the Maquine basin? basement by monazite and titanite crystals yielding 2100e1950 Ma Does the deposition of the Minas Supergroup track an entire UePb metamorphic ages (Machado et al., 1992; Schrank and Wilson cycle or did these rocks form during the opening and Machado, 1996a,b; Aguilar et al., 2015). The tectonomagmatic closure of an intracratonic rift basin? event affecting the southern Sao~ Francisco craton, which is usually What is the age and tectonic significance of the unconformity referred to as the Transamazonian orogeny such as for the bounded Piracicaba Group, whose depositional age is still poorly Amazonian Craton (e.g., Machado et al., 1996), has been named by constrained? Teixeira et al. (2015) the Minas accretionary orogeny. Why the UePb depositional age and age distribution obtained In the Orosirian, after the formation of the fold-and thrust belt by Machado et al. (1996) and Hartmann et al. (2006) for the the Quadrilatero underwent orogenic collapse, resulting in the rocks of the Sabara Groups are different (Fig. 11)? Does this deposition of the alluvial sandstones, conglomerates and pelites of discrepancy reflect the fact that the samples were collected from the Itacolomi Group and development of the dome-and-keel different localities and/or different stratigraphic positions? Ul- structure (Alkmim and Marshak, 1998). The large percentage of timately, what is the depositional age and age distribution of the Rhyacian detrital zircons (i.e. between 2300 and 2050 Ma) in the turbidites of the Sabara Group? conglomerates of the Itacolomi basins support a non-cratonic Monazite and titanites grains from the basement gave Rhyacian source (Machado et al., 1996; Alkmim and Marshak, 1998) sug- UePb ages, while no metamorphic zircon crystals/overgrowths gesting that most of the sediments were derived from terrains yielded non-Archean ages. What are the metamorphic condi- generated during the Minas accretionary orogeny. tions attained by the basement during the Minas orogeny? On a regional scale, the Minas accretionary orogeny correlates What is the geographic extent of the Rhyacian metamorphic with the tectonic-magmatic events recognized in the Itabuna-Sal- overprint? Why no magmatism was produced in the Quad- vador-Curaça belt in the northern portion of the Sao~ Francisco rilatero Ferrífero during the continental collision between the craton (Teixeira et al., 2015). These events seem to reflect the as- Sao~ Francisco and Congo protocratons? sembly of a supercontinent during the Orosirian period, the Atlantica supercontinent (Rogers, 1996), followed by Columbia Acknowledgements (Rogers and Santosh, 2004; Zhao et al., 2004), whose re- constructions, though not fully accomplished, have progressed This paper was supported by CNPq (grant numbers: 401334/ significantly in the last few years. 2012-0; 402852/2012-5 and 302633/2011-1) and FAPEMIG (grant numbers APQ03943 and RDP 0067-10) grants. We thank two anonymous reviewers for the constructive comments that helped 10.5. Questions for future research improving the quality of this work. Prod. V. Janasi is acknowledged for the editorial guidance offered. Recently, new geochronological data helped improve our un- derstanding of the ca. 1.5 Ga of evolution of the Quadrilatero Fer- Appendix A. Supplementary data rífero (Lana et al., 2013; Romano et al., 2013; Mendes et al., 2014; Farina et al.,; 2015a). However, a number of questions remain Supplementary data related to this article can be found at http:// opened for further researches, as outlined below: dx.doi.org/10.1016/j.jsames.2015.10.015.

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